Systems and methods to confirm that an autostereoscopic display is accurately aimed

ABSTRACT

A autostereoscopic display system includes an autostereoscopic display configured to project images representing a left-eye view and a right-eye view of an image, an emitter configured to emit a tracer beam having a directional relationship to that of the projected images, a sensor configured to detect reflections of the tracer beam, and a processing circuit. The processing circuit is configured to control an emission of the tracer beam, receive feedback data from the sensor, use the feedback data to determine an impact site on the viewer corresponding to the tracer beam and adjust a direction of the tracer beam based on the impact site.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 13/665,563, filed Oct. 31, 2012, which is incorporated hereinby reference in its entirety and for all purposes.

BACKGROUND

Autostereoscopic arrays direct different scenes to each of a viewer'seyes. This can be used, for example, to generate perception of 3D depthin images, or to display separate images to each viewer. However, if theaiming is not accurate, it can result in poor quality viewing. Thus, inaddition to tracking a viewer, there is a need for the autostereoscopicarray to confirm that the projected images are indeed projected to theviewer's eyes.

SUMMARY

One exemplary embodiment relates to an autostereoscopic display system,including an adjustable autostereoscopic display configured to projectimages representing a left-eye view and a right-eye view of an image, anemitter configured to emit a tracer beam having a directionalrelationship to that of the projected images, a sensor configured todetect reflections of the tracer beam, and a processing circuit. Theprocessing circuit is configured to control an emission of the tracerbeam, receive feedback data from the sensor, and use the feedback datato determine an impact site on the viewer corresponding to the tracerbeam and adjust a direction of the tracer beam based on the impact site.

Another exemplary embodiment relates to a method of aiming stereoscopicimages, including configuring an adjustable autostereoscopic display toproject images representing a left-eye view and a right-eye view of animage, controlling an emission of a tracer beam having a directionalrelationship to that of the projected images, receiving feedback datafrom a sensor configured to detect reflections of the tracer beam, andusing the feedback data to determine an impact site on the viewercorresponding to the tracer beam adjust a direction of the tracer beambased on the impact site.

Another exemplary embodiment relates to a non-transitorycomputer-readable medium having instructions stored thereon, theinstructions include instructions to configure an adjustableautostereoscopic display to project images representing a left-eye viewand a right-eye view of an image, instructions to control an emission ofa tracer beam having a directional relationship to that of the projectedimages, instructions to receive feedback data from a sensor configuredto detect reflections of the tracer beam, and instructions to use thefeedback data to determine an impact site on the viewer corresponding tothe tracer beam and adjust a direction of the tracer beam based on theimpact site.

The invention is capable of other embodiments and of being carried outin various ways. Alternative embodiments relate to other features andcombinations of features as may be generally recited in the claims.

The foregoing is a summary and thus by necessity containssimplifications, generalizations and omissions of detail. Consequently,those skilled in the art will appreciate that the summary isillustrative only and is not intended to be in any way limiting. Otheraspects, inventive features, and advantages of the devices and/orprocesses described herein, as defined solely by the claims, will becomeapparent in the detailed description set forth herein and taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

The invention will become more fully understood from the followingdetailed description taken in conjunction with the accompanying drawingswherein like reference numerals refer to like elements, in which:

FIG. 1 is a schematic diagram of an autostereoscopic display system,including an adjustable autostereoscopic display, an emitter, a sensor,and a processing circuit, shown according to an exemplary embodiment.

FIG. 2 is a block diagram of an adjustable autostereoscopic display, anemitter, a sensor, and a processing circuit, shown according to anexemplary embodiment.

FIG. 3 is a detailed block diagram of a processing circuit, shownaccording to an exemplary embodiment.

FIG. 4 is a schematic diagram of an autostereoscopic display system,including an adjustable autostereoscopic display, an emitter, a sensor,and a processing circuit, shown according to an exemplary embodiment.

FIG. 5 is a schematic diagram of an autostereoscopic display system,including an adjustable autostereoscopic display, a sensor, and aprocessing circuit, shown according to an exemplary embodiment.

FIG. 6 is a schematic diagram of an autostereoscopic display system,including an adjustable autostereoscopic display, emitters, a sensor,and a processing circuit, shown according to an exemplary embodiment.

FIG. 7 is a schematic diagram of tracer beams and impact sites, shownaccording to an exemplary embodiment.

FIG. 8 is a schematic diagram of a tracer beam and an impact site, shownaccording to an exemplary embodiment.

FIG. 9 is a flow diagram of a process for confirming that an adjustableautostereoscopic display is accurately aimed at a viewer, shownaccording to an exemplary embodiment.

FIG. 10 is a schematic diagram of light rays of an adjustableautostereoscopic display, shown according to an exemplary embodiment.

FIG. 11 is a schematic diagram of light rays of an adjustableautostereoscopic display, shown according to an exemplary embodiment.

FIG. 12 is a schematic diagram of a projection system of an adjustableautostereoscopic display, shown according to an exemplary embodiment.

DETAILED DESCRIPTION

Before turning to the figures, which illustrate the exemplaryembodiments in detail, it should be understood that the application isnot limited to the details or methodology set forth in the descriptionor illustrated in the figures. It should also be understood that theterminology is for the purpose of description only and should not beregarded as limiting.

Referring generally to the figures, systems and methods for confirmingthat an adjustable autostereoscopic display is accurately aimed at aviewer are shown and described. An adjustable autostereoscopic displaymay be an autostereoscopic display configured in a manner as to allowthe adjustment of the direction and focus of light rays emittedtherefrom. Other aspects of the light rays (e.g., modulation, intensity,etc.) may also be adjustable. The adjustable autostereoscopic displaymay use a parallax barrier, lenticular array, micromirrors, or any othersuitable means of adjusting its light rays. A person may be viewing suchan autostereoscopic display (e.g., a 3D television, a computer display,a handheld gaming device, or any other adjustable autostereoscopicdevice) and may have separate images projected to his or her eyes. Ifthe person alters his or her position with respect to the display andany projected images, the projected images may no longer be hitting theperson's eyes, leading to a poor viewing experience. For example, theprojected 3D images may lose their appearance of depth, or the projectedimages may appear to be blurry. A viewer's location and eyes may betracked, and the projections adjusted in an attempt to continue to hitthe viewer's eyes. This may be achieved without any viewer-mountedequipment. In this manner, a better viewing experience may be providedto the viewer. However, this type of method for controlling theprojection directions constitutes open-loop control. Such systems use asensor to determine where the projections should be sent (i.e., to theviewer's eyes) and then use a control mechanism (for instance, lateralmotion of an array of parallax barriers or lenticules) to direct theprojections to this proper location. While such systems are designed toaim the projections to the location identified by the sensor, theygenerally do not actually confirm that the projections do in factaccurately hit their target. Accordingly, the system may believe it isaccurately delivering projections to the viewer's eyes, while in fact itis not, causing the viewer to suffer from an unsatisfying viewingexperience. It is therefore of interest to provide a closed-loopprojection system, which detects where on the viewer the projectionshit, and adjusts their aimpoint to ensure that the projections properlyreach the eyes of the viewer. For additional discussion of an open-loopsystem that utilizes a parallax device, see, e.g., U.S. Pat. No.6,377,295 to Woodgate, et al.

In one embodiment, a closed-loop projection system uses a tracer beam,emitted by an emitter. The emitter may be a separate emitter whichprojects a tracer beam of light. Alternatively, the emitter may be theautostereoscopic display itself, where the tracer beam is encoded (e.g.,time encoding, spectral encoding, etc.) within the display'sprojections. The direction of the tracer beam has a known (generallyfixed) relationship to that of the display's projections; for instance,it might be in the same direction as the left or right projection, mightbe midway between them, or the like. In an embodiment, the direction ofthe tracer beam is controlled by the same adjustment system thatcontrols the direction of the projection beams, such that thedirectional relationship remains fixed as the direction of the tracerbeam or the projections is adjusted. In other words, as a control systemshifts the aim of the tracer beam, the projections undergo acorresponding shift, and vice versa. In an embodiment, the projectionsystem can comprise two parallel, closely spaced arrays, a source arraycontaining light sources, and a beam array containing beam definingelements, such as parallax barriers collimator slits, or lenticules. Thesource array can include light sources defining display pixels, and canalso contain one or more emitter sources used for the tracer beam; theemitter and display sources may be shared or separate. The beam arraymay contain elements which interact with display sources to form theprojection beams as well as one or more elements which interact with theemitter(s) to form one or more tracer beams. By occupying fixedlocations on common array surfaces, the projection beams and the tracerbeam can be configured to have a defined directional relationship (e.g.,the tracer beam may be midway between the two projections, may be aboveor below them, etc.). As the two surfaces are laterally displaced inorder to steer the beams towards a moving viewer, the directionalrelationship between the projection beams and the tracer beam ismaintained; the surfaces may undergo corresponding angular motion. Asensor (e.g., a camera, a photodetector, etc.) may receive feedbackcorresponding to where on a viewer the tracer beam hits. The sensor maybe the same sensor used to track a viewer. Based on the feedback, aprocessing circuit may be used to adjust the direction of the tracerbeam (and accordingly that of the projections) so that they hit adesired impact site (e.g., the viewer's eyes, the viewer's forehead,etc.). In this way the processing circuit may confirm that the tracerbeam hits a known site on the viewer, and hence (via the knowndirectional relationship between the tracer beam and the projections)can confirm that the projections reached the viewer's eyes. Theprojection impacts are confirmed by the processing circuit without theuse of any viewer-mounted equipment. Additionally, a viewer's head andeyes may be tracked using a sensor (e.g., a camera, etc.), and thisinformation may also be used in adjusting the tracer beam, andconfirming projections from the autostereoscopic display. According to acontemplated scenario, a person may be watching a 3D movie on anautostereoscopic television, configured according to the systems andmethods herein. The person is seated in one location on his or hercouch. The television projects stereoscopic images to the eyes of theperson, still seated in the same position. The person may adjustpositions and move to the other side of the couch. The television uses asensor to detect the changed position of the person and locate the newposition of the person's head. The television set then automaticallyadjusts the projection of stereoscopic images so that they reach theperson's eyes. The television confirms via a tracer beam that theprojections are properly reaching the person's eyes. In this manner, theperson may enjoy the 3D movie in the new position, with the appropriateleft and right images automatically reaching the person's left and righteyes, respectively.

According to another contemplated scenario, a man and woman may beplaying a gaming system coupled to an autostereoscopic television, whichis configured according to the systems and methods herein. Thetelevision projects two different images to the man and womansimultaneously, each corresponding to content relating to theircharacter in the game (e.g., the man would see game video contentrelated to his character, and the woman would see game video contentrelating to her character, etc.). The man and woman may alter their headpositions while playing the game, and the television detects the changedpositions using a sensor, and automatically adjust the projections sothat they continue to reach the eyes of the man and woman, respectively.The television confirms via tracer beams that the projections areproperly reaching the man's eyes and woman's eyes. In this manner, theman and woman may play a game at the same time, on the same television,with the appropriate images reaching their left and right eyes,respectively. The images remain accurately aimed despite the man andwoman changing their head positions.

For purposes of this disclosure, the term “coupled” means the joining oftwo members directly or indirectly to one another. Such joining may bestationary in nature or moveable in nature and such joining may allowfor the flow of electricity, electrical signals, or other types ofsignals or communication between the two members. Such joining may beachieved with the two members or the two members and any additionalintermediate members being integrally formed as a single unitary bodywith one another or with the two members or the two members and anyadditional intermediate members being attached to one another. Suchjoining may be permanent in nature or alternatively may be removable orreleasable in nature.

Referring to FIG. 1, autostereoscopic display 100 is shown.Autostereoscopic display 100 is adjustable and includes emitter 102,sensor 106, and processing circuit 108. Tracer beam 104 and viewer 110are also shown. Autostereoscopic display 100 is depicted as a 3Dtelevision, however it may be computer monitor, a gaming device, acellular phone, or any other device that includes an adjustableautostereoscopic display. Emitter 102 may be configured to emit a tracerbeam 104. Tracer beam 104 may be tracer light, visible light of a narrowband, ultra violet light, infrared light, or any other suitable signal.Tracer beam 104 has a directional relationship to that of the projectedimages. Tracer beam 104 is generally projected in the same direction asthat of the images intended to reach a viewer's eyes. For example,tracer beam 104 may be emitted in a direction that is above, below, inbetween, or offset from the projected images. Emitter 102 may be aseparate module coupled to autostereoscopic display 100, or may beautostereoscopic display 100 itself, configured to embed a tracer beamwithin its projections. There may be a single emitter 102, or aplurality of emitters 102. Sensor 106 is used to detect reflections oftracer beam 104 and reflections of any other projections. Sensor 106 maybe a camera, or any other sensor capable of detecting an impact site(e.g., a photodetector, etc.). Sensor 106 may also be configured totrack the head and eye location of viewer 110. Processing circuit 108may compare the reflections of tracer beam 104 to a desired impact site.A desired impact site may be the eyes, nose, center of forehead,midpoint between the eyes, etc., of viewer 110. Processing circuit 108is depicted as the processing circuit embedded in autostereoscopicdisplay 100.

It should be understood, that the systems and methods of the presentdisclosure are not limited based on the type of autostereoscopic displaydevice, the type of the emitter, or the type of sensor. A variety ofemitters and sensors are envisioned.

Referring to FIG. 2, a block diagram of a system 200 for executing thesystems and method of the present disclosure is shown. System 200includes emitter 202, adjustable autostereoscopic display 204, sensor206, and processing circuit 208. Emitter 202 may be a separate deviceconfigured to emit a tracer beam. Alternatively, emitter 202 may beautostereoscopic display 204 itself, configured to embed a tracer beamwithin its projections. Sensor 206 may detect reflections of a tracerbeam, and provide information corresponding to detected reflections toprocessing circuit 208. Processing circuit 208 controls the generationof the tracer beam and the direction of the tracer beam and of theprojections of autostereoscopic display 204. Emitter 202, sensor 206,and processing circuit 208 are coupled to autostereoscopic display 204.While depicted as separate modules in FIG. 2, emitter 202,autostereoscopic display 204, sensor 206, and processing circuit 208 maybe part of one device. The systems and methods of the present disclosureare not limited to a single emitter, but any number of emitters 202 maybe used.

According to an exemplary embodiment, autostereoscopic display 204 is a3D projection television, processing circuit 208 is the processingcircuit within the television, emitter 202 and sensor 206 are a lightgeneration device and a camera, respectively, both embedded in thetelevision's housing. According to another exemplary embodiment,autostereoscopic display 204 is a digital light projection (DLP)projector, processing circuit 208 is the processing circuit within theprojector, sensor 206 is a camera, and emitter 202 is the projectionmechanism of the projector. According to another exemplary embodiment,autostereoscopic display 204 is an LED projector, processing circuit 208is the processing circuit within the projector, sensor 206 is a camera,and emitter 202 is the projection mechanism of the projector.

Referring to FIG. 3, a more detailed block diagram of processing circuit300 for completing the systems and methods of the present disclosure isshown, according to an exemplary embodiment. Processing circuit 300 maybe processing circuit 108 of FIG. 1. Processing circuit 300 is generallyconfigured to control the emission of a tracer beam and adjust theoutput of an autostereoscopic display to maintain accurate aiming. As anexample, the tracer beam may be projected as light from anautostereoscopic display, or as light from a separate emitter.Processing circuit 300 may generate signals necessary to cause a tracerbeam to start or stop. Processing circuit 300 may also generate signalsto cause a tracer beam to modulate or change positions, etc. Processingcircuit 300 is further configured to receive an input from an outsidesource (e.g., a sensor, a camera, components within an autostereoscopicdisplay, etc.). Input may be received continuously or periodically.Processing circuit 300 is configured to process the received input andgenerate signals necessary to adjust the tracer beam and projections ofan autostereoscopic display. Processing circuit 300 uses the input andtracer beam to confirm projections are properly reaching a viewer.Processing circuit 300 may also be configured to track a viewer'slocation.

Processing circuit 300 includes processor 312. Processor 312 may beimplemented as a general purpose processor, an application specificintegrated circuit (ASIC), one or more field programmable gate arrays(FPGAs), a group of processing components, or other suitable electronicprocessing components. Processing circuit 300 also includes memory 302.Memory 302 is one or more devices (e.g., RAM, ROM, Flash Memory, harddisk storage, etc.) for storing data and/or computer code forfacilitating the various processes described herein. Memory 302 may beor include non-transient volatile memory or non-volatile memory. Memory302 may include database components, object code components, scriptcomponents, or any other type of information structure for supportingthe various activities and information structures described herein.Memory 302 may be communicably connected to the processor 312 andinclude computer code or instructions for executing the processesdescribed herein.

Memory 302 includes configuration data 304. Configuration data 304includes data relating to processing circuit 300. For example,configuration data 304 may include information relating to interfacingwith an autostereoscopic display. This may include the command setneeded to interface with video display components, for example, aparallax barrier, a lenticular array, a micromirror array, or otheroptical splitter, etc. Configuration data may include specification andprotocol information for the components of an autostereoscopic displayas described herein. As another example, configuration data 304 mayinclude information relating to tolerances or error levels, which may beused in determining when a projected image should be adjusted.Configuration data 304 may include data to configure the communicationbetween the various components of processing circuit 300, and thevarious components of the systems described herein.

Configuration data 304 may further include scheduling information. Thescheduling information may be used by processor 312 to enable or disablecertain components of the systems described herein. For example,configuration data 304 may specify that at a certain time only the headand eye tracking methods described below will be enabled, and displayadjustment methods will be disabled. In an exemplary embodiment, thescheduling information specifies how often the processing circuit (e.g.,processing circuit 300) will attempt to confirm that theautostereoscopic display is accurately aimed at a viewer. For example,the systems and methods to confirm projection accuracy may run everyfive seconds, etc. Configuration data 304 may further include timinginformation corresponding to a timing pattern of the tracer beam. Forexample, configuration data 304 may store a timing pattern to beprovided to data analysis module 310 and tracer beam controller 308,which uses the pattern to pulse the tracer beam in a defined manner(e.g., every other microsecond, etc.). However, the scope of the presentapplication is not limited to any defined schedule or particular timingpattern.

Memory 302 includes memory buffer 306. Memory buffer 306 is configuredto receive data from a sensor, (e.g. sensor 206 in FIG. 2) through input314. Memory buffer may also receive data through input 314 from othercomponents within an autostereoscopic display. The data may includeimage or video data, tracer beam data, radar information, lightdetection and ranging information, or infrared information. The image orvideo data, for example, may be data provided by a camera. The datareceived through input 314 may be stored in memory buffer 306 untilmemory buffer 306 is accessed for data by the various modules ofprocessing circuit 300. For example, data analysis module 310 may accesscamera data that is stored in memory buffer 306.

Memory 302 includes tracer beam controller 308. Tracer beam controller308 is configured to control the generation and spatial positioning of atracer beam. Tracer beam controller 308 receives emitter specificationinformation from configuration data 304, corresponding to a type ofemitter being used. Tracer beam controller 308 receives information fromdata analysis module 310 corresponding to a viewer's location. This may,for example, include coordinates according to a coordinate system inone, two, or three dimensions. This information may also includedistance and angle information. As another example, this information mayrepresent estimated future locations of a viewer. As another example,viewer information may represent specific characteristics of the viewer(e.g., right eye, left eye, first viewer, second viewer, specific vieweridentity, etc.). Tracer beam controller 308 interprets this information,and adjusts the tracer beam (or tracer beams) in order to implement thesystems and methods disclosed herein.

The tracer beam may be comprised of light suitable for detection by asensor. The light of the tracer beam may be provided by a separateemitting device or by the scene light of a projection of theautostereoscopic display. In an exemplary embodiment, the tracer beam isconfigured to use light that is not perceptible to a viewer. In oneexample, an LED is configured to emit light for use as a tracer beam. Inanother example, the autostereoscopic display is projecting lightcorresponding to images of a scene, and the tracer beam is the fullscene light or is embedded within the scene light. The tracer beam maybe of an intensity greater or lesser than light of the projected images.Tracer beam controller 308 includes all logic necessary for controllingthe emission pattern and characteristics of the tracer beam.

In one embodiment, a separate emitter is configured to emit a tracerbeam having a defined spectral signature. The spectral signature of thetracer beam is used to distinguish the tracer beam from non-tracer beamprojections. As an example, the tracer beam may be light outside aviewable band (e.g., infrared, ultra-violet, etc.) As another example,the tracer beam may be visible light of a specific narrow-bandwidth. Asanother example, the tracer beam may be of light of a certainpolarization. Tracer beam controller 308 is configured to control theemissions of the tracer beam. This may include enabling or disabling thetracer beam, pulsing the tracer beam, increasing or decreasing theintensity of the tracer beam, changing the position of the tracer beam,modulating the tracer beam, etc. Tracer beam controller 308 providesdata corresponding to the tracer beam emission pattern and location todata analysis module 310.

In another embodiment, the autostereoscopic display is configured toencode a tracer beam within its projections. The autostereoscopicdisplay may be a flat panel display that uses lenticular arrays,parallax-barriers, micromirrors, or other optical splitters. Tracer beamcontroller 308 is configured to control the encoded emissions of thetracer beam. As an example, the tracer beam may be light from theautostereoscopic display of a specified narrow band. As another example,the tracer beam may be light of an intensity level that is above theintensity level of the background scene. Tracer beam controller 308generates the necessary signal for the display to send time-gated pulses(e.g., microsecond pulses, etc.) of tracer beam light according to adefined timing pattern. The timing pattern may be based on a schedulestored in configuration data 304 or memory buffer 306. The timingpattern may be such that the tracer beam is emitted when one or both ofimages representing a left-eye view or right-eye view are not projected.As another example, the timing pattern may be provided by configurationdata 304. Tracer beam controller 308 maintains the timing pattern andintensity, and provides pattern and intensity information to dataanalysis module 310, which may then use the information indistinguishing the tracer beam from other non-tracer beam light. Dataanalysis module 310 may also use information provided by tracer beamcontroller 308 while tracking the spatial location of a viewer.

Tracer beam controller 308 may be configured for use with multipletracer beams and multiple emitters. It should be understood that thescope of the present application is not limited to a certain number oftracer beams or emitters.

Memory 302 includes data analysis module 310. Data analysis module 310receives tracer beam information from tracer beam controller 308. Dataanalysis module 310 further receives configuration information fromconfiguration data 304. Additionally, data analysis module 310 receivessensor information, which is provided by a sensor (e.g. sensor 206 ofFIG. 2) through input 314. Data analysis module 310 may also scan theinput, determine, and track a viewer's location, and represent thelocation in data. The location data may be used through the variousmodules of processing circuit 300. As an example, data analysis module310 may apply facial recognition algorithms using the sensorinformation, and may classify and organize a viewer, and the location ofthe viewer's face. As another example, data analysis module 310 mayapply motion detection algorithms using the sensor information, and maydetermine when a viewer is changing positions. Data analysis module 310may also apply eye-detection algorithms to determine the left and righteye locations of a viewer, and may adjust an aiming point correspondingto detected eye locations. Data analysis module 310 may be configuredfor use with multiple viewers. It should be understood that the scope ofthe present application is not limited to any certain number viewers.

The configuration information received by data analysis module 310includes data corresponding to the current system utilizing processingcircuit 300. For example, this may include information of the number oftracer beam emitters of an autostereoscopic display. This may alsoinclude information relating to the emitter, sensor, andautostereoscopic display specifications. For example, the informationmay be related to the focal length or angle of view of a camera beingused as a sensor.

Data analysis module 310 provides information to tracer beam controller308, so that tracer beam controller may adjust a tracer beam. In anexemplary embodiment, data analysis module 310 receives configurationinformation corresponding to a type of desired impact site. A desiredimpact site may be a location on a viewer that the tracer beam orprojections are intended to hit. As an example, in an embodiment thatuses scene light with an encoded tracer beam, desired impact sites mayinclude the left-eye for light from the left-eye channel, and the righteye for light from the right-eye channel. As another example, in anembodiment that uses a separate emitter to generate a central tracerbeam, a desired impact site may be a nose, or a midpoint between theeyes, etc. Data analysis module 310 may access the impact site typeinformation and the sensor information. Data analysis module 310 maygenerate facial location information of a viewer as described above, andmay use the facial location information to generate spatial data of thedesired impact site. Data analysis module 310 may provide the desiredimpact site data to tracer beam controller 308, which uses the data toadjust the tracer beam's aiming point accordingly. As an example, thedata may be coordinates according to a coordinate system in one, two, orthree dimensions.

Data analysis module 310 may generate signals necessary to adjust aprojection of an autostereoscopic display (e.g., autostereoscopicdisplay 204 of FIG. 2). The autostereoscopic display may utilize anynumber of techniques for projecting images (e.g., flat panels usinglenticular arrays, parallax-barriers, micromirrors, optical splitters,etc.) The projected images may be adjusted by controlling the deflectionsystem of the display, or other aspects of the display. As an example,deflection systems may utilize a variety of different optical deflectors(e.g., electrically or mechanically controlled) to control the directionand focus of light rays emitted from the display.

In an exemplary embodiment, data analysis module 310 determines aviewer's location as described above. The viewer's location includes thelocation of the viewer's eyes. Data analysis module 310 sends theappropriate signals to the deflection system of the display in order tocause the deflectors to adjust such that the direction and focus oflight reaches the viewer's eyes. Data analysis module 310 may use thelocation of the viewer's eyes in determining an aiming point of theautostereoscopic display. For example, the deflectors are adjusted suchthat projections of light intended for either the left eye or right eye,will be aimed at the left eye or right eye, respectively. In practice,the direction of deflection for each eye may be slightly different foreach pixel of the display screen due to the position of the pixel. Inother embodiments, data analysis module 310 may provide viewer locationinformation to the deflection system, which may determine the directionof deflection with respect to a reference pixel, and deflect the lightfrom each pixel based on a predefined relationship between the referencepixel and each other pixel.

Data analysis module 310 confirms that a projection is correctlyreaching the eyes of the viewer. Data analysis module 310 scans sensordata provided through input 314, where the sensor is configured todetect reflections of the tracer beam, and to detect scene lightprojected from the autostereoscopic display. Data analysis module 310compares the tracer beam reflection data to a desired impact site andcalculates measurements relating to the comparison. This may includedistances, coordinates, etc. Data analysis module 310 uses themeasurements to confirm that the direction and focus of light raysemitted from the display are accurately aimed at a viewer. As anexample, if data analysis module 310 determines that the tracer beamreflection is not close to the desired impact site, data analysis module310 may generate signals necessary to adjust a projection direction asdiscussed above. In another example, a certain tolerance level may bespecified by configuration data 304. Data analysis module 310 may usethe tolerance level in confirming the projection, and may adjust theprojection only if a measurement from a desired impact site to an actualimpact site exceeds the tolerance level.

Data analysis module 310 may determine an offset using the tracer beam'saiming point and a direction of a projected image. For example, while anopen-loop control system of the display may use sensor informationconcerning the location of the viewer's eyes to adjust the projectiondirections so as to nominally cause the projections to arrive at theviewer's eyes, analysis of tracer beam reflections may indicate that theprojections are actually offset, for instance by 10 mrad upwards and 8mrads to the left. Rather than apply this correction directly viaclosed-loop control with each video frame, data analysis module 310 mayuse the offset to calibrate the autostereoscopic display, therebyimproving the accuracy of the open-loop control system. Given thiscalibrated offset, the control system can thereafter (for some period oftime) use open-loop control augmented by the offset. In someembodiments, the use of this type of tracer-calibrated open-loop controlis a viable alternative to performing full closed-loop correction foreach video frame. For example, data analysis module 310 may compare theaiming point of the tracer beam and an aiming point of theautostereoscopic display. Data analysis module 310 may generate signalsnecessary to adjust the autostereoscopic in order to reduce the offsetto a desired value and bring the tracer beam's impact site and theimpact site of the projected images closer together. Data analysismodule 310 may confirm the calibration by scanning sensor data providedthrough input 314, where the sensor is configured to detect reflectionsof the tracer beam, and to detect scene light projected from theautostereoscopic display. Calibration of the autostereoscopic displaymay be performed sporadically (i.e., not for each video frame), or maybe based on a time limit or schedule. As an example, configuration data304 may contain a calibration schedule where the autostereoscopicdisplay is calibrated after every 8 hours of use. In another example,calibration may occur when the autostereoscopic display is powered on oractivated. In another example, calibration may occur in response to arequest provided via input 314, sent from a system of theautostereoscopic display (e.g., a user voice command, a commandinitiated by a remote control, a calibration monitoring system of theautostereoscopic display, etc.).

In one embodiment, the tracer beam is configured use light at a 360 nmwavelength, and the sensor is a camera capable of detecting 360 nm lightin addition to detecting visible light wavelengths. Data analysis module310 is configured to scan for 360 nm light within the sensor reflectiondata. If data analysis module 310 detects the 360 nm light, it willdetermine the location of 360 nm reflected light, and compare thelocation to the desired impact site location. Data analysis module 310will use the comparison data to either confirm or deny that theautostereoscopic display is accurately projecting. If the display is notaccurately projecting, data analysis module 310 may use the comparisondata to adjust the direction and focus of the tracer beam or light raysemitted from the display in order to aim them at the desired impactsite. When the reflected tracer beam light is within an acceptable rangefrom a desired impact site, the autostereoscopic display may beconfirmed to be accurately aimed. This process may repeat as necessary(e.g., when data analysis module 310 detects a changed position of aviewer, or per a schedule, etc.).

In one embodiment, scene-light is used for the tracer beam, and thetracer beam is encoded within the scene-light using time gatingtechniques. As an example, the tracer beam may pulse for one microsecondaccording to a pattern controlled by tracer beam controller 308. Thetracer beam may operate during such pulses at significantly greaterintensity than the normal scene light, thereby enhancing itsdetectability by a time synchronized sensor. Data analysis module 310receives reflection data from the sensor, as described above. Dataanalysis module 310 may first distinguish left-eye and right-eyechannels of light from each other by using the time gating pattern (forsequential emission displays), or by using spectral or polarizationdifferences between light in the left-eye and right-eye channels (as anexample, some autostereoscopic displays use polarization or spectraldifferences to output the left and right beams in different directions).Data analysis module 310 scans for the tracer beam within the reflectiondata representing the left and right channels reflections of light. Dataanalysis module 310 uses the tracer beam pattern data provided fromtracer beam controller 308 to determine time slots to scan for thetracer beam.

Referring to FIG. 4, autostereoscopic display system 400 is shownaccording to an exemplary embodiment. Autostereoscopic display system400 includes adjustable autostereoscopic display 408, sensor 406,processing circuit 404, and emitter 402. Autostereoscopic display 408may be a 3D computer monitor. Emitter 402 may be an ultraviolet LED,sensor 406 may be a camera or any other suitable photodetector, andprocessing circuit 404 may be the processing components of the monitor.In an alternative embodiment, processing circuit 404 includes theprocessing components of a computing device coupled to the monitor.According to an exemplary embodiment, emitter 402 is configured to emita tracer beam, and sensor 406 is configured to detect reflections oflight. Processing circuit 404 is configured to communicate with thecamera and LED. Processing circuit 404 is further configured to controlthe direction and focus of light rays emitted from the monitor as wellas that of the tracer beam from the emitter so that they maintain adirectional relationship. This and other similar embodiments are usefulin situations where 3D computing applications are required. As anexample, a researcher using the monitor to view the helix structure ofDNA would have an improved experience, as the monitor would track andconfirm that its projections are accurately aimed. In an alternativeembodiment, emitter 402 may be an infrared transmitter. In yet anotherembodiment, emitter 402 may be an LED of visible light, but of a narrowband.

Referring to FIG. 5, autostereoscopic display system 500 is shownaccording to an exemplary embodiment. Autostereoscopic display system500 includes adjustable autostereoscopic display 502, processing circuit504, and sensor 506. Autostereoscopic display 502 may be a 3D televisiondisplay. Sensor 506 may be a camera and processing circuit 504 may bethe processing components of the television. In this embodiment, thetracer beam is emitted by the television display by encoding tracerlight in its projections (e.g., projections of light corresponding to amovie scene, etc.) and the camera is configured to detect reflections oflight. The tracer beam may be encoded using time gating or spectral orpolarization techniques as mentioned herein, or the full light from oneor both of the projections may serve as the tracer beam. All componentsnecessary to generate the tracer beam may be embedded within the displaycomponents of the television (e.g., a pixel generating device, amicromirror array, a DLP projection system, etc.).

Referring to FIG. 6, autostereoscopic display system 600 is shownaccording to an exemplary embodiment. Autostereoscopic display system600 includes adjustable autostereoscopic display 608, sensor 606,processing circuit 604, and emitters 602. Autostereoscopic display 608may be a 3D television display. Sensor 606 may be a camera andprocessing circuit 604 may be the processing components of thetelevision. Emitters 602 may be ultraviolet LED devices, and may bepositioned in various locations around adjustable autostereoscopicdisplay 608. In this manner, tracer beams can be sent from multiplelocations on the display. Processing circuit 604 may perform additionalanalysis utilizing the different locations of the emitters in order tomore accurately confirm that the display is properly aimed at a viewer.Processing circuit 604 may track reflections from the different tracerbeams in aggregate or individually. Each emitter may be calibratedsimilarly or differently, and may be configured for different aimingpoints or impact sites. As an example, each emitter may be configured touse different wavelengths of light. In another example, all emitters mayemit tracer beams of the same wavelength.

In one exemplary embodiment, emitters on the left half of a display areconfigured to aim at viewers positioned on the left half of the display.Similarly, emitters on the right half of a display are configured to aimat viewers positioned on the right half of the display. Emitters in thecenter of the display are configured to aim at all viewers. In thismanner, processing circuit 604 may accept data from all of the emittersand use the data to more accurately aim and confirm projections comingfrom the display.

Referring to FIG. 7, desired impact sites 706 and 708 on viewer 700 areshown according to an exemplary embodiment. Tracer beams 702 and 704 arealso shown. Desired impact sites 706 and 708 are the right eye and lefteye of viewer 700, respectively. The locations of desired impact sites706 and 708 are determined by a processing circuit (e.g., processingcircuit 300 of FIG. 3). The type of desired impact site may be specifiedby a configuration file (e.g. configuration data 304 of FIG. 3). Forexample, the type of desired impact site may be a nose, an eye, aforehead, etc. Tracer beams 702 and 704 correspond to the right and leftlight channels of a projection. As an example, tracer beam 702 maycorrespond to light intended to reach the right eye of a viewer, andtracer beam 704 may correspond to light intended to reach the left eyeof a viewer. The light intended to reach a viewer may be generated by asimultaneous autostereoscopic display (e.g., where the left and rightbeams are projected simultaneously). In another example, the lightintended to reach a viewer may be generated by a sequentialautostereoscopic display (e.g., where the left and right beams areprojected sequentially). Tracer beams 702 and 704 are depicted asreflecting off of right eye and left eye of viewer 700, respectively.The reflections may be detected by sensor (e.g., sensor 206 of FIG. 2)and used to determine actual impact sites. The actual impact sites oftracer beams 702 and 704 may be compared to desired impact sites 706 and708. This information is used by the processing circuit to determine ifan adjustment to the autostereoscopic display needs to be made. Thisinformation is also used to confirm that the autostereoscopic display isaccurately aimed, as described above.

Referring to FIG. 8, desired impact site 804 on viewer 800 is shownaccording to an exemplary embodiment. Tracer beam 802 is also shown.Desired impact site 804 is the middle of the forehead of viewer 800. Thelocation of desired impact site 804 is determined by a processingcircuit (e.g., processing circuit 300 of FIG. 3). As discussed above, adesired impact site may be also specified by a configuration file (e.g.,configuration data 304 of FIG. 3). Tracer beam 802 corresponds to systemconfigured to use a single emitter. As an example, when the desiredimpact site is configured for a single location on a viewer (e.g., themiddle of the forehead, the nose, etc.), the processing circuit may thencalculate the locations of the right and left eye using that singlelocation. This can be accomplished any number of ways (e.g., using anumber representing the average separation between human eyes, using anoffset specified in configuration data, using measurement data from asensor detecting the eyes of the viewer, etc.) The reflections of tracerbeam 802 may be detected by sensor (e.g., sensor 206 of FIG. 2) and usedto determine an actual impact site. The actual impact site of tracerbeam 802 may be determined compared to desired impact site 804. Thisinformation is used by the processing circuit to determine if anadjustment to the autostereoscopic display needs to be made. Thisinformation is also used to confirm that the autostereoscopic display isaccurately aimed, as described above.

Referring to FIG. 9, a flow diagram of process 900 for confirming thatan autostereoscopic display is accurately aimed at a viewer is shown,according to an exemplary embodiment. Process 900 includes projectingimages representing a left-eye view and a right-eye view of an image(step 902), emitting a tracer beam having a directional relationship tothat of the projected images, and adjust the direction and focus oflight rays emitted from the display toward the desired impact site (step904), receiving reflection data from a sensor, analyze reflection datato determine an impact site (step 906), adjusting the direction of thetracer beam based on the impact site (step 908), and confirming that thetracer beam hit the impact site and the display is accurately aimed atthe viewer (step 910).

Referring to FIG. 10, a schematic diagram of light rays 1006 of anadjustable autostereoscopic display is shown according to an exemplaryembodiment. The light rays 1006 may consist of scene light, tracer beamlight, or both. The autostereoscopic display providing light rays 1006may be an autostereoscopic display as described herein (e.g.,autostereoscopic display 408 of FIG. 4, etc.). In particular, FIG. 10shows light rays 1006 deflecting towards left-eye 1008 of viewer 1012 ata first time-step (shown as solid lines), and light rays 1006 deflectingtowards right-eye 1010 of viewer 1012 at a second time-step (shown asdashed lines). Although the time steps are labeled “first” and “second”,no intended order of operations should be implied from the labels“first” or “second”. Light is emitted from light sources 1002, throughoptical deflectors 1004 towards the eyes of viewer 1012. As an example,light sources 1002 may be LED devices, or any other suitable lightsources. Although optical deflectors 1004 are shown as separate devices,optical deflectors 1004 may be part of a single-device deflectionsystem. The relative size of objects, such as the light sources andoptical deflectors, are not to any scale and may not be in proportion asthose in a particular implementation.

Referring to FIG. 11, a similar schematic diagram as FIG. 10 of lightrays 1114 is shown, as implemented by an autostereoscopic displayutilizing a lenticular array. The light rays 1114 may consist of scenelight, tracer beam light, or both. The autostereoscopic displayproviding light rays 1114 may be an autostereoscopic display asdescribed herein (e.g., autostereoscopic display 502 of FIG. 5, etc.).FIG. 11 depicts light sources 1102, which emit light rays 1114 thattransmit through optical deflectors 1104 and lenticules 1106 towards theeyes of viewer 1112. The optical deflectors may be electrically ormechanically controlled devices. The optical deflectors may bemechanically controlled devices, using lateral offsets between the lightsources 1102 and lenticules 1106 (or parallax barriers) to directprojections into desired directions. When used to adjust the display'saimpoint (e.g., to track a moving viewer) the optical deflectors(whether active or passive) are configured to apply correspondingangular deflections to both the projection beams and the tracer beam.Light rays 1114 are shown as deflecting towards left-eye 1108 of viewer1112 at a first time-step (shown as solid lines), and light rays 1114deflecting towards right-eye 1110 of viewer 1112 at a second time-step(shown as dashed lines). Although the time steps are labeled “first” and“second”, no intended order of operations should be implied from thelabels “first” or “second”. The relative size of objects, such as thelenticules and light sources, are not to any scale and may not be inproportion as those in a particular implementation. As shown, lenticules1106 passively (i.e., without requiring power or control) deflect thelight rays. In embodiments using lenticules, parallax barriers, and/orother non-controlled optical elements, the system may be configured toadjust for any optical effects. As an example, the system may adjustlight deflection, obstruction, scattering, absorption, reflection,polarization, etc. In such an embodiment, the system may be programmedeither with a particular adjustment or with instructions forautomatically determining an appropriate adjustment. A particularadjustment may also be stored within a configuration data file (e.g.,configuration data 304 of FIG. 3). As another example, a system maycalibrate optical deflectors by using a tracer beam, and implementingthe systems and methods described herein. In this manner, such a systemmay actively adjust the deflection system to confirm that light rays1114 representing a left-eye view and a right-eye view hit the left eyelocation and right eye location of viewer 1112, respectively.

It should be understood, that some embodiments may use a sequence oftiming other than that as depicted in FIGS. 10-11. For example, if onepixel must display views to two viewers, then, while theautostereoscopic display (e.g., autostereoscopic display 502 of FIG. 5)projects the right-eye view of the images, the processing circuit of thedisplay (e.g., processing circuit 300) may send appropriate signals tothe display's deflection system to cycle through deflecting imagestowards each viewer's right eye. Such a configuration may allow theautostereoscopic display to sequence at the same rate, regardless of howmany viewers are watching, without employing separate pixels for eachviewer. Other implementations are also envisioned (e.g., multiple setsof pixels corresponding to different views, etc.). The systems andmethods disclosed herein are not limited to a particular implementationor configuration of pixels.

Referring to FIG. 12, a schematic diagram of projection system 1200 ofan adjustable autostereoscopic display is shown according to anexemplary embodiment. Light rays 1214 may consist of projection beams(e.g., scene light), tracer beam light, or both. Projection system 1200includes source array 1204 containing light sources, and beam definingarray 1206 containing beam defining elements (e.g., parallax barriers,collimator slits, lenticules, etc.). In one embodiment, source array1204 and beam defining array 1206 are arranged in parallel and areclosely spaced apart. Source array 1204 may include light sourcesdefining display pixels that correspond to a left-eye view and aright-eye view for viewer 1202 (e.g., pixel sources 1208 and 1212,etc.). Source array 1204 may further include one or more emitter sources(e.g., emitter 1210) used to generate a tracer beam. Light sources andemitter sources may utilize shared components, or may be separate. Beamdefining array 1206 may contain elements which interact with sourcearray 1204 to form the projection beams as well as one or more elementswhich interact with the emitter(s) (e.g., emitter 1210) to form one ormore tracer beams. By occupying fixed locations on common arraysurfaces, the projection beams and the tracer beam can be configured tohave a defined directional relationship (e.g., the tracer beam may bemidway between left-eye view and right-eye view projections, or may beabove or below the projections, etc.). As the two surfaces are laterallyor angularly displaced in order to steer the beams towards viewer 1202,the directional relationship between the projection beams and the tracerbeam is maintained.

The construction and arrangement of the systems and methods as shown inthe various exemplary embodiments are illustrative only. Although only afew embodiments have been described in detail in this disclosure, manymodifications are possible (e.g., variations in sizes, dimensions,structures, shapes and proportions of the various elements, values ofparameters, mounting arrangements, use of materials, colors,orientations, etc.). For example, the position of elements may bereversed or otherwise varied and the nature or number of discreteelements or positions may be altered or varied. Accordingly, all suchmodifications are intended to be included within the scope of thepresent disclosure. The order or sequence of any process or method stepsmay be varied or re-sequenced according to alternative embodiments.Other substitutions, modifications, changes, and omissions may be madein the design, operating conditions and arrangement of the exemplaryembodiments without departing from the scope of the present disclosure.

The present disclosure contemplates methods, systems and programproducts on any machine-readable media for accomplishing variousoperations. The embodiments of the present disclosure may be implementedusing existing computer processors, or by a special purpose computerprocessor for an appropriate system, incorporated for this or anotherpurpose, or by a hardwired system. Embodiments within the scope of thepresent disclosure include program products comprising machine-readablemedia for carrying or having machine-executable instructions or datastructures stored thereon. Such machine-readable media can be anyavailable media that can be accessed by a general purpose or specialpurpose computer or other machine with a processor. By way of example,such machine-readable media can comprise RAM, ROM, EPROM, EEPROM, CD-ROMor other optical disk storage, magnetic disk storage or other magneticstorage devices, or any other medium which can be used to carry or storedesired program code in the form of machine-executable instructions ordata structures and which can be accessed by a general purpose orspecial purpose computer or other machine with a processor. Wheninformation is transferred or provided over a network or anothercommunications connection (either hardwired, wireless, or a combinationof hardwired or wireless) to a machine, the machine properly views theconnection as a machine-readable medium. Thus, any such connection isproperly termed a machine-readable medium. Combinations of the above arealso included within the scope of machine-readable media.Machine-executable instructions include, for example, instructions anddata which cause a general purpose computer, special purpose computer,or special purpose processing machines to perform a certain function orgroup of functions.

Although the figures may show a specific order of method steps, theorder of the steps may differ from what is depicted. Also two or moresteps may be performed concurrently or with partial concurrence. Suchvariation will depend on the software and hardware systems chosen and ondesigner choice. All such variations are within the scope of thedisclosure. Likewise, software implementations could be accomplishedwith standard programming techniques with rule-based logic and otherlogic to accomplish the various connection steps, processing steps,comparison steps and decision steps.

What is claimed is:
 1. An autostereoscopic display system, comprising:an adjustable autostereoscopic display configured to project imagesrepresenting a left-eye view and a right-eye view of an image; anemitter configured to emit a tracer beam having a directionalrelationship to the projected images; a sensor configured to detectreflections of the tracer beam; and a processing circuit configured to:control an emission of the tracer beam to emit the tracer beam when theleft-eye and right-eye views are not projected; receive feedback datafrom the sensor; use the feedback data to: determine an impact site onthe viewer corresponding to the tracer beam; and adjust a direction ofthe tracer beam based on the impact site to intercept a desired impactsite of the viewer.
 2. The system of claim 1, wherein the sensorincludes a camera.
 3. The system of claim 1, wherein the tracer beam isemitted in a direction that is the same as the projected imagesrepresenting the left-eye view.
 4. The system of claim 1, wherein thetracer beam is emitted in a direction that is the same as the projectedimages representing the right-eye view.
 5. The system of claim 1,wherein the tracer beam is emitted in a direction that is between theprojected images representing the left-eye view and right-eye view. 6.The system of claim 1, wherein the tracer beam is emitted in a directionthat is above the projected images representing the left-eye view andright-eye view.
 7. The system of claim 1, wherein the tracer beam isemitted in a direction that is below the projected images representingthe left-eye view and right-eye view.
 8. The system of claim 1, whereinthe tracer beam comprises at least one of infrared light, ultravioletlight, and visible light of a narrow-bandwidth.
 9. The system of claim1, wherein the tracer beam comprises a pulse of light.
 10. The system ofclaim 1, wherein emission of the tracer beam is controlled based on atiming pattern, the timing pattern based on a schedule.
 11. The systemof claim 1, wherein the processing circuit is further configured to:determine at least one of a left eye location and a right eye locationof the viewer; determine an aiming point corresponding to at least oneof the left eye location and the right eye location; and adjust theautostereoscopic display using the aiming point.
 12. A method of aimingstereoscopic images, comprising: configuring an adjustableautostereoscopic display to project images representing a left-eye viewand a right-eye view of an image; controlling an emission of a tracerbeam having a directional relationship to the projected images, whereinthe tracer beam is emitted when at least one of the left-eye andright-eye views are not projected; receiving feedback data from a sensorconfigured to detect reflections of the tracer beam; and using thefeedback data to: determine an impact site on the viewer correspondingto the tracer beam; and adjust a direction of the tracer beam based onthe impact site.
 13. The method of claim 12, further comprising:determining at least one of a left eye location and a right eye locationof the viewer; determining an aiming point corresponding to at least oneof the left eye location and the right eye location; and adjusting theautostereoscopic display using the aiming point.
 14. The method of claim13, wherein the processing circuit is further configured to determine anoffset using the aiming point and a direction of at least one of theprojected images representing the left-eye view and the right-eye view.15. The method of claim 14, wherein the processing circuit is furtherconfigured to calibrate the autostereoscopic display, wherein thecalibration comprises adjusting the offset using the impact site. 16.The method of claim 15, wherein the calibration is based on anactivation of the autostereoscopic display.
 17. The method of claim 15,wherein the calibration occurs according to a time limit.
 18. The methodof claim 15, wherein the calibration occurs according to a schedule. 19.The method of claim 15, wherein the calibration occurs according to acalibration monitoring system of the autostereoscopic display.
 20. Themethod of claim 15, wherein the calibration occurs according to a usercommand.
 21. The method of claim 12, wherein the adjustableautostereoscopic display includes a lenticular array.
 22. The method ofclaim 12, wherein the adjustable autostereoscopic display includes aparallax-barrier.
 23. The method of claim 12, wherein the adjustableautostereoscopic display includes optical splitters.
 24. The method ofclaim 12, further comprising controlling emissions of a plurality oftracer beams, wherein each tracer beam comprises light.
 25. The methodof claim 24, wherein the emissions of the plurality of tracer beams arecontrolled individually.
 26. The method of claim 24, wherein theemissions of the plurality of tracer beams are controlled in aggregate.27. A non-transitory computer-readable medium having instructions storedthereon, the instructions comprising: instructions to configure anadjustable autostereoscopic display to project images representing aleft-eye view and a right-eye view of an image; instructions to controlan emission of a tracer beam having a directional relationship to theprojected images, wherein the instructions control the emission of thetracer beam to emit the tracer beam when the left-eye and right-eyeviews are not projected; instructions to receive feedback data from asensor configured to detect reflections of the tracer beam; andinstructions to use the feedback data to: determine an impact site onthe viewer corresponding to the tracer beam; and adjust a direction ofthe tracer beam based on the impact site.
 28. The non-transitorycomputer-readable medium of claim 27, wherein the tracer beam comprisesinfrared light.
 29. The non-transitory computer-readable medium of claim27, wherein the tracer beam comprises ultraviolet light.
 30. Thenon-transitory computer-readable medium of claim 27, wherein the tracerbeam comprises visible light of a narrow-bandwidth.
 31. Thenon-transitory computer-readable medium of claim 27, wherein the tracerbeam is of an intensity greater than a maximum intensity of the imagesrepresenting the left-eye view and the right-eye view.
 32. Thenon-transitory computer-readable medium of claim 27, wherein theinstructions further comprise instructions to control emissions of aplurality of tracer beams, wherein each tracer beam comprises light. 33.The non-transitory computer-readable medium of claim 32, wherein theemissions of the plurality of tracer beams are controlled individually.34. The non-transitory computer-readable medium of claim 32, wherein theemissions of the plurality of tracer beams are controlled in aggregate.35. The non-transitory computer-readable medium of claim 27, wherein thetracer beam is a non-visible tracer beam.